Interleukin-1a (IL-1a), primarily a macrophage/monocyte product, is responsible for the host response to infection and inflammation. In addition, IL-1a potentiates hematopoiesis, affects vascular endothelium, enhances proliferation of some cells but is inhibitory to others, stimulates synthesis of other cytokines and growth factors and activates T and B cell function. While IL-1 is generally considered not to mediate direct tumor cytotoxic activity, cytotoxicity has been observed against selected human tumor cell lines. This phase I;II study will evaluate safety and efficacy of IL-1a given in combination with cyclophosphamide in patients with advanced cancer. It is, therefore, feasible that IL-1a can augment conventional chemotherapy.